American lunar logistics spacecraft. Study 1966. Many versions of new Lunar Logistic Vehicles (LLV's) using several possible candidate propellants were studied by NASA and its contractors in the mid-1960's for post-Apollo lunar base support.

By the time budget cutbacks ended such thoughts, NASA was favoring a two-stage version powered by throttleable RL10 engines burning liquid oxygen/liquid hydrogen propellants.

Limiting the propellant candidates to those being used in active NASA programs (earth storables of the N204/Aerozine 50 and cryogens of the L0X/LH2 type), the choice revolved about a tradeoff between 33% better Isp performance, poorer length to diameter configurations, and more extensive ground support requirements of LOX/LH 2 compared to N204/Aerozine 50. However, the performance increase did provide significantly larger payload capabilities, and accordingly, the cryogenic combination was chosen by NASA for the new LLV's. In addition to the conventional one stage configurations, two stage versions were also of interest. A typical two stage LLV consisted of a braking stage (LI) and a landing stage (LII). The advantages of staging were (i) payload improvement, (2) the landed vehicle had a lower center-of-gravity (reducing possible cargo unloading problems and landing gear requirements), and (3) the braking stage (LI) could be a general use propulsion stage for integration into earth orbital or planetary programs (Multi-Mission Module Concept).

LESA Lunar Base American manned lunar base. Cancelled 1968. LESA (Lunar Exploration System for Apollo) represented the ultimate lunar base concept studied by NASA prior to the cancellation of further Saturn V production in June 1968. More...

Lunar Landers Lunar lander design started with the British Interplanetary Society's concept of 1939, followed by Von Braun's 3964 tonne monster of 1953. It then settled down to more reasonably-sized variants. Landers came in three main types: two stage versions, with the first stage being a lunar crasher that would brake the spacecraft until just above the lunar surface, then separate, allowing the second stage to land on the surface; two stage versions consisting of a descent stage that went all the way to the surface, and an ascent stage that would take the crew from the surface to lunar orbit or on an earth-return trajectory; and single stage versions, using liquid oxygen/liquid hydrogen propellants. More...

Lox/LH2 Liquid oxygen was the earliest, cheapest, safest, and eventually the preferred oxidiser for large space launchers. Its main drawback is that it is moderately cryogenic, and therefore not suitable for military uses where storage of the fuelled missile and quick launch are required. Liquid hydrogen was identified by all the leading rocket visionaries as the theoretically ideal rocket fuel. It had big drawbacks, however - it was highly cryogenic, and it had a very low density, making for large tanks. The United States mastered hydrogen technology for the highly classified Lockheed CL-400 Suntan reconnaissance aircraft in the mid-1950's. The technology was transferred to the Centaur rocket stage program, and by the mid-1960's the United States was flying the Centaur and Saturn upper stages using the fuel. It was adopted for the core of the space shuttle, and Centaur stages still fly today. More...

Bibliography

Baker, David, The History of Manned Spaceflight, Crown, New York, 1981.

Soviets study NASA's ambitious plans - .
Nation: USSR. Spacecraft: LESA Shelter; LLV. NASA gave the US President a 130-page programme outlining plans for America's future space programme. The thing read to the Soviets like a science fiction novel, with reusable space ferries, huge orbital stations and lunar bases, nuclear rocket stages, and manned Mars expeditions. There was no way the Soviet Union could compete with such a programme -- and that was leaving unconsidered the massive American military space progamme. Additional Details: here....